Exploring a gorge in south-east France in 1994 for prehistoric artefacts, Jean-Marie Chauvet, squeezing through a narrow passage, found himself in a hidden cavern, the walls of which were covered with paintings of animals - beautiful images, which feature in Werner Herzog's recent documentary film, 'Cave of Forgotten Dreams'.
Radiocarbon dating suggested the images were between 30,000 and 32,000 years old, making them almost twice the age of the famous Lascaux cave art in south-west France.
Despite a comprehensive radiocarbon study published in 2001 that seemed to confirm that the paintings were indeed 30,000 years old, Paul Pettitt of the University of Sheffield, UK, and his colleagues were unconvinced.
To try to settle the controversy, Jean-Marc Elalouf of the Institute of Biology and Technology in Saclay, France, and his team have turned to the remains of cave bears. His team collected 38 samples of cave bear remains in the Chauvet cave. Radiocarbon dating showed the samples were all between 37,000 and 29,000 years old, hinting that by the end of that period they were extinct, at least locally. Samples from a nearby cave gave similar results.
"It is clear that the paintings are very ancient", says Elalouf. Pettitt remains unconvinced.